Cycles Render Output Black
Go to the Properties panel &gt; Render Layers tab &gt; Layer dropdown and erase BoneMaterial as your Material:

From the Wiki (regarding Material Override):

Overrides all material settings to use the Material chosen here.
Examples of where this might be used:

To check lighting by using a plain diffuse material on all objects

Render a wireframe of the scene

Create a custom render pass such as an anti-aliased matte or global coordinates.



You had inadvertently changed every material in the scene to one that did not render correctly.
EDIT:
Newer versions of blender don't use layers, but &quot;collections&quot; so the override function is in the scene&gt;View Layer section.

Additional info:
Where is the Layers panel in Blender 2.8?
2.8 - Is it possible to assign (override) a material to a whole collection?